A chiral LC–MS strategy for stereochemical assignment of natural products sharing a 3-methylpent-4-en-2-ol moiety in their terminal structures

A terminal 3-methylpent-4-en-2-ol (MPO) moiety is a common structural feature in various polyketide natural products. Stereochemical assignments of this moiety have mainly relied on computational analyses of NMR, ECD, and specific rotation data. However, none of these approaches can be applied to all compounds. In this study, we developed a method to determine the absolute configuration of the terminal MPO moiety with high accuracy and sensitivity by a combination of chemical degradation, chemical synthesis, and chiral LC-MS analysis. The applicability of this method was demonstrated through the stereochemical assignment of (+)-capsulactone (<b>1</b>).